Ukrainian President Petro Poroshenko has announced a new initiative to bring a halt to fighting in eastern Ukraine.

In a statement issued on his website on December 4, Poroshenko said Ukraine's military will halt fire beginning on December 9 in eastern Ukraine, on a "Day of Silence."

Poroshenko said the measure was included in a broader cease-fire deal signed in Minsk on September 5.

Russian news agency RIA Novosti quoted rebel leaders in the breakaway regions of Donetsk and Luhansk as confirming such a measure was included in the Minsk agreement, but it was unclear whether they would abide by it.

The September 5 truce has been regularly violated, and more than 1,000 people have been killed since.

Earlier this week, a cease-fire for Donetsk airport broke down hours after being implemented.

Andrei Purgin, the self-styled parliament speaker of the self-declared Donetsk People's Republic, confirmed the December 9 truce in comments to Russia's RIA Novosti state news agency.

However, Igor Plotnitsky, the self-styled head of the neighboring self-declared Luhansk People's Republic, said no written agreement on a specific date was ever reached.

"There was a verbal agreement [about a cease-fire] for around that date," Plotnitsky told RIA Novosti. "But we do not have written confirmation of this yet."

'Hybrid' Cease-Fire

Commenting on the news, Didier Burkhalter, the chairman of the Organization for Security and Cooperation in Europe (OSCE), cautioned that "there are a number of different points that are not clear for the time being."

Burkhalter was speaking on the sidelines of an OSCE conference in Basel focused on defusing the crisis in eastern Ukraine.

Addressing that gathering, Ukrainian Foreign Minister Pavlo Klimkin stressed the need for a real cease-fire, and not just the "hybrid" currently in tatters.

"It is not a Ukrainian crisis, it is not an OSCE crisis, it is about Russian aggression," said Klimkin.

U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov later briefly met on the sidelines of the OSCE gathering.

Ahead of those talks, Kerry said the West was not seeking confrontation with the Kremlin, and blamed Moscow for isolating itself "through its own actions" in Ukraine.

Ukraine and Western countries have accused Russia of fueling the crisis in eastern Ukraine by supplying the separatists with heavy weapons and fighters, charges which Moscow denies.

Kerry also repeated earlier calls he has made for the September 5 cease-fire agreement to be enforced.

That message was later echoed by Lavrov after his talks with Kerry.

Lavrov said both the United States and Russia support the OSCE mission in eastern Ukraine.

Lavrov also repeated Moscow's position that Kyiv should open a dialogue with the pro-Russia separatists in eastern Ukraine.